Heat exchanger



May 14, 1935, DORMER 2,001,186

HEAT EXCHANGER Filed May 31, 1953 Patented May 14, 1935 UNITED STATESPATENT OFFICE Claude Dornier, Friedrichshafen, Germany,

slgnor of one-half to Dornier-Metallbauten G. in.

b. H., Friedrichshafemfiermany Application May 31, 1933, Serial No.673,653 In Germany July 23, 1932 4 Claims. (Cl. 25'l1 39) My inventionrelates to heat exchangers such as radiators for power plants onaircraft, and more particularly to heat exchangers made of light metalor a light-metal alloy throughout.

Heretofore attempts to manufacture suitable radiators from light metalor a light-metal alloy have failed because no satisfactory connectioncould be established between the light metal body of the radiatorincluding the frame or casing, the water chamber or chambers and theconnecting pipes on the one hand and the tubes forming the radiatorblock proper on the other hand. It has therefore been suggested toconnect the parts by beading-over without soldering or welding, gut};l1it was found that such connections are not It is an object of myinvention to provide a heat exchanger which does not show thesedrawbacks. To this end I connect the light metal frame, water chambersand connecting pipes by welding and I coat the ends of the tubes formingthe block with a metal which is closely related to and bears the same(plus or minus) sign as the light metal or light-metal alloy ofthe pipesin the series of electrical potential. This metal may for instance benickel if-the tubes are of pure aluminium. On this coating I arrange alayer of a metal suchas tin which is suitable for soldering.

In the drawing afiixed to this specification and forming part thereof aradiator embodying my invention is illustrated diagrammatically by wayof example.

In the drawing Fig. 1 is a central longitudinal section and Fig. 2 is anend elevation of the radiator, while Fig. 3 is a section on the lineIIIIII in Fig. 2, drawn to a larger scale.

Referring to the drawing, i is the body or casing of the radiator, 2 and3 are water chambers at its upper and lower ends, and t and 5 are thepipe connections for the water flowing through the radiator.

The end walls of the radiator are provided with openings and inwardlyprojecting flanges t and l surrounding these openings.

8 are the radiator tubes, oniyone of which is shown in Figs. 1 and 3. 9,it are the tube ends which are prismatic, as shown in Fig. 2.

The flanges 6 and l are coated with. a metal of the kind described, suchas nickel. A similar coating is applied to the prismatic ends 9 and IIIof the tubes 8, and to this coating is applied a coating of a suitablesoldering metal such as tin. The tubes are assembled to form a blockwhose individual tubes are soldered together at their prismatic ends,-the ends of the block being soldered to the flanges B and l.

The partsv forming the body or casing i and the water chambers 2 and 3are connected by 5 welding and the pipe connections t and 5 are weldedto the body or casing.

I thus obtain a light metal radiator the parts of which are connected bywelding and soldering.

The body or casing i with its water chambers 10 2 and 3 (any desirednumber of such water-distributing and water-collecting chambers beingprovided) and the pipe connections 4 and 5 may be made of pure aluminiumor some other light metal or light-metal alloy which is weldable. Theparts of the body or casing are connected to each other and to the pipeconnections 4 and 5 by welding, as described. The tubes 8 forming theradiator block are also made of pure aluminium, or some other lightmetal or light-metal alloy, but it is not necessary that they should beof the same material as the body or casing i. The tubes are solderedtogetherto form the block. The coated soldering faces of the tubesextend only a short distance inwardly from their ends. .This isunimportant feature ofmy invention because it has been found that tubesmade of light metal or a light-metal alloy, if coated with a solderinglayer, are corroded much more rapidly by water than uncoated tubes. Bylimiting the coating to the points where this is required, i. e., to theprismatic ends 9 and ill of the tubes, the

, life of the tubes is prolonged.

The finished tube block is soldered to the frame or casing i.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described for obviousmodifications will occur to a person skilled in the art.

I claim:.

1. A heat exchanger comprising in combination, a light metal frame,water chamber and connecting pipe, a block of light metal radiatortubes,

a layer of a metal closely related to and bearing the same sign in theseries of electric potential as said light metal being arranged on theends of said tubes exclusively and a soldering metal coating said metallayer and firmly connecting the ends of adjoining tubes to one another.

2. A heat exchanger comprising in comblnation, a light metal frame,water chamber and connecting pip'e connected by welding, a block oflight metal radiator tubes, a layer of a metal closely related toandbearing the same sign in the series of electric potential as saidlight metal being arranged on the ends of said tubes exclusively and asoldering metal coating said metal layer and firmly connecting the endsof adjoining tubes with one another.

3. A heat exchanger comprising in combination, a light metal frame,water chamber and. connecting pipe, a block of light metal radiatortubes, and a nickel layer arranged on the ends of said tubes,exclusively, soldering metal connecting the nickel layers on adjoiningtubes.

4. A heat exchanger comprising in combinatlon, a. light metal frame,water chamber and connecting pipe, a block of light metal radiatortubes, and a nickel layer arranged on the ends of said tubesexclusively, a layer of tin connecting the nickel layers on the ends ofadjoining tubes.

CLAUDE DORNIER.

